1. Field
The present invention relates to the field of portable digital music players and the use of these devices in a vehicle.
2. Description of the Related Art
Portable digital music players are changing how consumers listen to music. Hard drive based devices such as Apple Computer's iPod family, Sony's Network Walkman, Creative Labs' NOMAD, and Dell Computer's DJ may store libraries of songs in a variety of formats including MP3 (MPEG Layer III), AAC (Advanced Audio Coding), WMA (Windows Media Audio), WAV, AIFF, and Ogg Vorbis. Smaller flash-based devices made by iRiver, Samsung, Rio, and Philips offer less storage space but even smaller physical sizes. Wireless communication devices such as cellular telephones and personal digital assistants (PDAs) can also be portable digital music players. Portable digital music players also use integrated displays that present information including the current track title and artist, or the file hierarchy of the tracks stored. Using internal batteries, these devices allow a user to play and take their music anywhere.
Many products exist that allow portable digital music players to play music stored in portable digital music players through the speakers of a vehicle. These products typically use one of two approaches. In the first approach, a short-range FM radio transmitter is attached to the portable digital music player and the vehicle radio is tuned to the frequency of the transmitter. The use of such a transmitter is subject to radio interference which may cause undesired results. Typically, these transmitters draw power from the portable digital music player and thereby drain the batteries of the player. Additionally, personal FM transmitters are illegal in certain countries, such as the United Kingdom, and are not a viable solution to using a portable digital music player in a vehicle.
The second approach uses a wired connection to electrically attach a portable digital music player to an input of the existing vehicle radio. Examples of this type of connection include BMW's iPod adapter solution, Alpine's KCA-420i adapter, Dension's ice>Link:iPod, and a standard cassette adapter. The wired connection typically results in a cable draped across the vehicle interior. These cables are unsightly and may interfere with driving. Often wired approaches are combined with add-on accessory cradles. These cradles have non-durable mounting methods that often detach inadvertently, however, some do provide power to the player. Vehicle-suitable translation of the user interface and controls of the player are not provided by this approach leaving a user to have to control the player using the controls of the player itself.
Another way of playing MP3s in a vehicle uses a standard or modified hard drive as a storage device for a car stereo. There are three basic variants of this setup. In the first variant, a standard hard drive in a custom casing is inserted into a head-end unit. The hard drive stores digital music files. However, there is no internal power source and an AC adaptor is required for use of the hard drive outside of the car stereo. A built-in display is also not included for the hard drive casing. Just simple playback buttons are provided. The head-end unit has no flexibility in what hard drive case it accepts. In the second variant, a standard hard drive is installed in a custom casing. This casing is then externally connected to the existing car stereo through inputs provided by the car stereo. In the third variant, a hard drive is permanently mounted inside the head-end unit.
Some car stereos are able to read MP3s from CD-R and CD-RW discs. Generally, these stereos do not have a display capable of depicting file information such As artist and/or song name. Nor do these stereos easily navigate through a long list of Content.